A study in which it has participated the Upper Council of Scientific Investigations (CSIC) has developed a method to measure the population of wolves on a regional scale based on procedures of capture-recapture spatially-explicit techniques and analysis of DNA non-invasive.
The work, which was published in Scientific Reports, stresses the need to develop policies for the conservation of the wild life. This requires reliable methods of measuring the population for greater acceptance and support in decision-making. In this sense, the wolf is one of the species most problematic in the measurements.
The research is based on methods spatially-explicit, i.e., that takes into account the spatial distribution of the detections. With this, it aims to solve the two most common problems in the traditional techniques of capture-recapture: the uncertainty in the definition of the effective area of sampling and the heterogeneity in detection.
“The strategy used in our study, we believe that it can effectively be used for monitoring populations of large carnivores such as the wolf, characterized by the spatial requirements of large and low densities”, explains José Jiménez, CSIC researcher at the Institute of Research in Hunting Resources.
The systems of capture-recapture were combined with the observations and follow-up genetic non-invasive analysis of stool. So, these modern techniques of analysis allow to estimate the size of populations and their spatial location.“The approach used in our work may be relevant to the case of the monitoring of threatened populations or populations subject to management, where it is necessary a high precision,” says Jimenez.
Traditionally, in the studies at the regional scale, we have used the number of herds to estimate the status of populations of the species.
However, the researchers note that, though the current can be measured with greater reliability the number of herds of wolves, sometimes, it is also necessary to estimate the abundance of the species and not only on the number of herds. In fact, after the study of the selected area in the Costa da Morte (Galicia), it was found that between 16 and 25% of the population of wolves was not linked to any group.
In total, the selected area of study, it was estimated that the average density was of 2.55 wolves per 100 km2, and the population size estimated was established in 111,6 wolves, with a credibility interval between 81,8 and 153,6 members of the species.
López-Bao JV, Godinho R, Pacheco C, García E, Motto FJ, Llaneza L, Palacios V, Jiménez J. Toward reliable population estimates of wolves by combining spatial capture-recapture models and non-invasive DNA monitoring. Scientific Reports, DOI: 10.1038/s41598-018-20675-9.